In the medical and dental fields, instruments and equipment used in examination and treatment are contaminated by various organic materials including blood and tissue fragments. These materials must be removed from the instrument's surface prior to heat sterilization to permit proper sterilization and clean appearance. These solid substances cling to the instruments and equipment and are difficult to remove without the use of mechanical devices, especially after the solids have dried. Hand washing using a brush or other suitable device with detergent followed by rinsing may satisfactorily clean the instruments but is time consuming and is subject to error by the human washer.
It has become common practice to use ultrasonic devices to provide the energy necessary to loosen the soils from dirty instruments and to use various cleaning agents, including detergents, to improve the efficiency of cleaning. A typical cleaning process involves placing the soiled instruments into an ultrasonic cleaning device with warm water and detergent, soaking the instruments for 5 to 120 minutes, applying ultrasonic energy for 15 to 60 minutes, removing the instruments from the device, rinsing with warm water and then sterilizing the instruments. Typically, liquid cleaners containing surfactants, chelating compounds, buffers, and other ingredients are diluted with water in the ultrasonic cleaning device. A typical dilution is one (1) ounce of detergent mixed per one (1) gallon of water. The typical ultrasonic apparatus holds from 1 quart to 5 gallons of solution. Dilutions require the user to pour and measure the required dose of the cleaning solution or the manufacturer of the detergent may provide some type of integrated measuring/dispensing device on its containers. This dose must be mixed with the proper amount of water either in the ultrasonic device if appropriate or in a separate container. As the cleaning solution becomes dirty quickly and should be replaced every one to four cycles and at least every day, large volumes of detergent must be stored and handled. Pouring and measuring, even with devices integrated into the detergent container, is messy and often inaccurate leading to waste and incomplete cleaning.
Due to the proteinaceous nature of the soils common to dental and medical instruments and equipment the use of proteolytic enzymes has been shown effective in improving the removal of these materials from these instruments and equipment. The use of a proteolytic enzyme in combination with a surfactant is taught in U.S. Pat. No. 5,234,832 to Disch et al. which teaches the cleaning and sterilization of medical endoscopes, particularly heat and corrosion sensitive endoscopes made of flexible glass fiber, using a solution of surfactant, proteolytic enzyme and an aldehyde disinfectant. One problem with preparations such as taught by Disch et al, is that storage of liquid enzymes for prolonged periods, especially after dilution and unless refrigerated, can lead to inactivation of the enzyme which reduces or eliminates cleaning performance.
The use of effervescent preparations of cleaning substances has been taught in the prior art. U.S. Pat. No. 4,252,664 to Inamorato, teaches a granular detergent composition with two types of granules, one type containing detergent and the other type containing effervescing agent and other ingredients, which may be a proteolytic enzyme. The composition is taught for use in clothes-washing machines. U.S. Pat. No. 5,055,305 to Young teaches a denture cleansing tablet comprising a bleaching agent and an effervescing agent. U.S. Pat. No. 3,962,107 to Levin et al. teaches a denture cleaning tablet comprising an enzyme and an effervescing agent.
Accordingly, there is a need for an effective cleaning compound for use in cleaning medical and dental instruments and equipment in ultrasonic cleaning devices which eliminates the storage, mixing, handling and waste problems associated with the current products.